Dentist&#39;s flask.



J. B. BUCHANAN.

DENTISTS FLASK. APPLICATION FILED APR.15, 1908.

963,418. I Y Paten tedJuly5g1910.

JAMES B. BUCHANAN, OF CHICAGO, ILLINOIS.

DENTISTS FLASK.

coasts.

Specification of Letters Eaten Patented J uly 5, 1910.

Application filed April 15, 1908. Serial No. 427,117.

To all whom 'it may concern:

Be it known that 1, JAMES B. BUCHANAN, citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Dentists Flasks;

and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to a novel construction in a flask for use bydentists in casting artificial teeth, the object being to provide asimple and eflicient device of this character, and consists in thefeatures of construction andcombinations of parts hereinafter fulldescribed and claimed.

In theaccompanying drawings illustrating this invention: Figure -1 is aview of theflask devoid of the plaster-of-paris filling, showing themain and auxiliary sprue in place preparatory to introducing thefilling. Fig. -2 is a central vertical section of the main sprue. Fig.3-- is a cen tral vertical longitudinal section of the flask showing thesame ready to receive the metal to be cast, the wax pattern andauxiliary sprue having been melted out and the main sprue removed. Fig.-4- is a top plan view of the flask showing the main sprue in .positiontherein.

The invention resides more particularly in the specific form andarrangement in a flask of main and auxiliary sprues whereby the metal tobe cast is prevented from overflowing and is guided into the patterncavity through a funnel shaped passage which latter is generally partlyfilled with excess metal, said pattern cavity and passage beinghorizontally disposed so that centrifugal force applied Wlll produceuniform density in the casting.

A feature of my invention consists also in the formation by large cavityin the flask, the bottom of which is disposed below the lowermost pointin the'funnel shaped passa e so that the metal to be cast may be meltein said cavity and subsequently by rotating the flask carrier be forcedby the resulting centrifugal force to flow into the pattern cavity.

My said flask consists preferably of a rectangular tube A of sheet metalopen at both ends'and provided in one wall with a circular opening Bthrough which the main curved that the main sprue of a sprue sprue C isadapted to project into the said tube A. Said sprue C resembles in forma distorted thimble and consists of a cup, the bottom portion of whichis disposed eccentrio to the rim portion,'the peripheral wall of saidcup being oint as at D which said bulged portion proects beyond theremaining portion of the wall lying between the same and the rim, saidrim being bordered by an annular flange E. Said portion of the wallcontaining the said bulge D is ogee curved in vertical section and theopposing portion is so when the said cup is turnec upon the free edge ofthe flange E at the point disposed in vertical alinement with the bulgeD as a fulcrum, no part of said opposing portion will strike the wall ofthe cavity formed by the sprue. In other words the curvature of the saidopposing portion is eccentric to the above mentioned point in the freeedge of the flange E, the lowermost portion of the cup being disposed atless radial distance from said point than is the meeting point of saidopposing portion I with the diametrically opposite point in the flangeE. At said bulge D I provide a plurality of needle oint projections Fsubstantially horizontal y disposed upon which the larger end of a.conical wax sprue G is secured, the latter being molded in the cavity Hin the filling I of the sprue C, the apex end of said wax sprue G beingcompressed against and thus secured to the crown end of the wax patternJ of the tooth to be cast.

After mounting the sprue G on the sprue C and mounting the pattern J onthe sprue G, said sprue G is inserted in the opening B in the tubularcasing A of said flask as shown in Fig. -1. Said casing A is then filledwith plastic plaster-of-paris and after the latter is set the sprue C isremoved. The sprue G and pattern H remain embedded in thelaster-of-paris and are melted out by heatmg'the flask. The latter isthen mount ed on the arm K of a rotatable spindle and firmly secured tothe latter in any suitable manner, said flask being so positioned thatthe pattern cavity is farthest removed from the axis of rotation of thearm K. The

metal is now introduced in a finely divided cold state into the cavity Lformed by the C and is melted by applying heat preferably by means of ablow pipe. As soon as the said metal is molten the spindle is revolvedat'considerable speed so that bulged outwardly at one while introducingthe plastic the resulting centrifugal force.throws the metal into thepattern cavity of the flask, such centrifugal force serving also tocause any air to be displaced and thus form a casting of uniform densityas is well known. The delivery end of the funnel shaped passage M formedby the sprue G beln very small enables surplus metal to be easi ysevered from the casting as will be obvious.

The device is very simple, efiicient and easily operated and enablescastings tobe made which coincide in the minutest details with thepattern.

claim as my invention:

1. A flask comprising a tubular shell provided with an opening, a'mainsprue comprising a cup laterally and having the portion of its wallopposing said bulged portion disposed eccentric tothe rim of the cup inalinement. with I said bulged portion, a projecting pin on the latteradapted to receive andsecure a wax sprue thereto, said wax sprue beingadapted to support thewax pattern of the tooth filling in the andadapted to form porting the wax bulged at one point flask, said mainsprue forming a melting cup in said flask having its bottom portiondisposed below the juncture therewith of the passage leading to thepattern cavity.

2. A flask comprising a tubular shell provided with an opening, a mainsprue rojecting through said opening and provided with a laterallyextended lower end portion a lateral extension of the mam'cavity of theflask, a wax sprue adapted to be secured to said laterally extendedportion of said main sprue and suppattcrn at its free end,

said main cavity formed by said main s rue constituting the melting potand exten ing below the mouth of the pattern (aivity formed by the waxsprue.

In testimony whereof I have signed my name in presence of twosubscribing nesses.

JAMES B. BUCHANAN.

Witnesses:

ARTHUR W. CAPS, RUDOLPH WM. Lorz.

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